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Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts

BACKGROUND: The feeding apparatus of salamanders consists mainly of the cranium, mandible, teeth, hyobranchial apparatus and the muscles of the cranial region. The morphology of the feeding apparatus in turn determines the boundary conditions for possible food processing (i.e., intraoral mechanical...

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Autores principales: Schwarz, Daniel, Konow, Nicolai, Porro, Laura B., Heiss, Egon
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7667761/
https://www.ncbi.nlm.nih.gov/pubmed/33292303
http://dx.doi.org/10.1186/s12983-020-00373-x
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author Schwarz, Daniel
Konow, Nicolai
Porro, Laura B.
Heiss, Egon
author_facet Schwarz, Daniel
Konow, Nicolai
Porro, Laura B.
Heiss, Egon
author_sort Schwarz, Daniel
collection PubMed
description BACKGROUND: The feeding apparatus of salamanders consists mainly of the cranium, mandible, teeth, hyobranchial apparatus and the muscles of the cranial region. The morphology of the feeding apparatus in turn determines the boundary conditions for possible food processing (i.e., intraoral mechanical reduction) mechanisms. However, the morphology of the feeding apparatus changes substantially during metamorphosis, prompting the hypothesis that larvae might use a different food processing mechanism than post-metamorphic adults. Salamandrid newts with facultative metamorphosis are suitable for testing this hypothesis as adults with divergent feeding apparatus morphologies often coexist in the same population, share similar body sizes, and feed on overlapping prey spectra. METHODS: We use high-speed videography to quantify the in vivo movements of key anatomical elements during food processing in paedomorphic and metamorphic Alpine newts (Ichthyosaura alpestris). Additionally, we use micro-computed tomography (μCT) to analyze morphological differences in the feeding apparatus of paedomorphic and metamorphic Alpine newts and sort them into late-larval, mid-metamorphic and post-metamorphic morphotypes. RESULTS: Late-larval, mid-metamorphic and post-metamorphic individuals exhibited clear morphological differences in their feeding apparatus. Regardless of the paedomorphic state being externally evident, paedomorphic specimens can conceal different morphotypes (i.e., late-larval and mid-metamorphic morphotypes). Though feeding on the same prey under the same (aquatic) condition, food processing kinematics differed between late-larval, mid-metamorphic and post-metamorphic morphotypes. CONCLUSIONS: The food processing mechanism in the Alpine newt changes along with morphology of the feeding apparatus during ontogeny, from a mandible-based to a tongue-based processing mechanism as the changing morphology of the mandible prevents chewing and the tongue allows enhanced protraction. These results could indicate that early tetrapods, in analogy to salamanders, may have developed new feeding mechanisms in their aquatic environment and that these functional innovations may have later paved the way for terrestrial feeding mechanisms.
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spelling pubmed-76677612020-11-17 Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts Schwarz, Daniel Konow, Nicolai Porro, Laura B. Heiss, Egon Front Zool Research BACKGROUND: The feeding apparatus of salamanders consists mainly of the cranium, mandible, teeth, hyobranchial apparatus and the muscles of the cranial region. The morphology of the feeding apparatus in turn determines the boundary conditions for possible food processing (i.e., intraoral mechanical reduction) mechanisms. However, the morphology of the feeding apparatus changes substantially during metamorphosis, prompting the hypothesis that larvae might use a different food processing mechanism than post-metamorphic adults. Salamandrid newts with facultative metamorphosis are suitable for testing this hypothesis as adults with divergent feeding apparatus morphologies often coexist in the same population, share similar body sizes, and feed on overlapping prey spectra. METHODS: We use high-speed videography to quantify the in vivo movements of key anatomical elements during food processing in paedomorphic and metamorphic Alpine newts (Ichthyosaura alpestris). Additionally, we use micro-computed tomography (μCT) to analyze morphological differences in the feeding apparatus of paedomorphic and metamorphic Alpine newts and sort them into late-larval, mid-metamorphic and post-metamorphic morphotypes. RESULTS: Late-larval, mid-metamorphic and post-metamorphic individuals exhibited clear morphological differences in their feeding apparatus. Regardless of the paedomorphic state being externally evident, paedomorphic specimens can conceal different morphotypes (i.e., late-larval and mid-metamorphic morphotypes). Though feeding on the same prey under the same (aquatic) condition, food processing kinematics differed between late-larval, mid-metamorphic and post-metamorphic morphotypes. CONCLUSIONS: The food processing mechanism in the Alpine newt changes along with morphology of the feeding apparatus during ontogeny, from a mandible-based to a tongue-based processing mechanism as the changing morphology of the mandible prevents chewing and the tongue allows enhanced protraction. These results could indicate that early tetrapods, in analogy to salamanders, may have developed new feeding mechanisms in their aquatic environment and that these functional innovations may have later paved the way for terrestrial feeding mechanisms. BioMed Central 2020-11-16 /pmc/articles/PMC7667761/ /pubmed/33292303 http://dx.doi.org/10.1186/s12983-020-00373-x Text en © The Author(s) 2020 Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
spellingShingle Research
Schwarz, Daniel
Konow, Nicolai
Porro, Laura B.
Heiss, Egon
Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts
title Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts
title_full Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts
title_fullStr Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts
title_full_unstemmed Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts
title_short Ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in Alpine newts
title_sort ontogenetic plasticity in cranial morphology is associated with a change in the food processing behavior in alpine newts
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7667761/
https://www.ncbi.nlm.nih.gov/pubmed/33292303
http://dx.doi.org/10.1186/s12983-020-00373-x
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